Modern astronomy suggests that planets are plentiful in the Universe and that the conditions suitable for life are commonplace. Advances in biochemistry have pointed out the unity of the biosphere and lead to the belief that all life had a common chemical origin. Laboratory experiments indicate that almost all the building blocks of life can be synthesized under simulated primitive Earth conditions. The analysis of meteorites and the study of the interstellar medium indicate that molecules of biological interest are commonplace in the Universe, thus leading to the conclusion that the evolutionary process which has taken place on Earth may have also occurred elsewhere in the cosmos leading to extraterrestrial civilisations.